Reference Model
Maniraptor Bird Model
This model comes out of a conference talk, "Feathered Dinosaurs? Avian Traits Associated with Feathered Maniraptorans," which tests a simple hypothesis: birds have feathers, and dinosaurs do not — meaning many animals labeled "feathered dinosaurs" may in fact be birds. Using the Turner et al. (2021) cladistic dataset (157 taxa, 853 characters — the same dataset behind the Baraminer tool below), the analysis built a feathered control group of 29 known birds and a dinosaur control group of 11 known non-avian theropods, then measured roughly 50 characters unique to the feathered group across three categories — hindlimbs and locomotion, wings and flight, and head and neck — against a test group of 116 maniraptoran taxa.
Family by family, the results found that dromaeosaurs, troodontids, oviraptorosaurs, and scansoriopterygids consistently grouped with birds rather than dinosaurs, while compsognathids, ornithomimosaurs, and therizinosaurs remained on the dinosaur side (alvarezsaurs were ambiguous). Rather than the gradual dinosaur-to-bird transition assumed by evolutionary models, the data matched the prediction of two distinct groups — animals that are either fully avian or fully dinosaurian, with no true transitional forms. The model and artist guidelines below translate those anatomical findings into a practical reference for reconstructing maniraptorans accurately.
Related Diagram
Maniraptor Artist Guidelines
Cladistics Analysis Tool
Baraminer
Baraminer is a browser-based tool for exploring published cladistic character matrices — comparing taxa, filtering traits by anatomical region, and testing how sets of animals group together across a dataset.
Open Baraminer →Frequently Asked Questions
What is a maniraptoran?+
Maniraptora is the group of theropod dinosaurs that includes dromaeosaurs, troodontids, oviraptorosaurs, scansoriopterygids, alvarezsaurs, and therizinosaurs — the animals most often labeled "feathered dinosaurs." Every fossil with true, clearly branching feathers found so far comes from inside this one group, which is exactly what led to this research: testing whether those animals are better classified as feathered dinosaurs, or simply as birds.
What’s the difference between a feather and a filament?+
A true feather has a rachis (the central quill) and branching barbs, and comes in several recognized types (symmetric, asymmetric, semiplume, filoplume, bristle, and downy). A filament has none of that: no barbs, no barbules, no branching, and no follicles. This study deliberately treated filaments and feathers as different things — filaments were more likely collagen or muscle/tendon fibers, frill support structures, scale-like spines, or a rare hair-like integument, not proto-feathers. Being strict about that distinction kept the results conservative.
How was the Maniraptor Bird Model built, and how accurate is it?+
The model is built on the Turner et al. (2021) cladistic dataset (157 taxa, 853 characters), cross-checked with a literature review and a visual review of skeletal photos and reconstructions. Two control groups were defined from well-established animals — 29 taxa with true feathers (mostly living and extinct birds) and 11 taxa everyone agrees are dinosaurs — and compared to find characters present in the feathered group and absent in the dinosaur group. Only anatomical traits were used (behavior, metabolism, and other inferred traits were excluded), and disarticulated fossils were left out of the control groups, since incomplete, scattered bones aren’t reliable enough to build a baseline from. That process turned up 50 characters unique to the feathered group, which were then tested against the remaining 116 maniraptoran taxa to see how they sorted.
Why does this differ from mainstream evolutionary reconstructions?+
Evolutionary models predict a gradual accumulation of bird traits across a spectrum of transitional forms. This study predicted the opposite — a clear line separating fully avian and fully dinosaurian animals — and that’s what the data showed: animals with more complete, well-articulated fossil data consistently landed clearly on one side or the other, while the animals that looked "transitional" were almost always the ones with the most missing or disarticulated data. In other words, the appearance of transitional forms tracked with incomplete data, not with genuine intermediate anatomy.
Was Velociraptor really a bird?+
According to this study’s criteria, yes — Velociraptor scored more avian traits than both Archaeopteryx and Microraptor, animals already widely accepted as birds. That result was a surprise, since popular depictions (built more on movie franchises than fossils) make Velociraptor hard to picture as anything but a scaly monster. The real animal was roughly turkey-sized, closely related to Zhenyuanlong, a dromaeosaur already found with wing feathers. Velociraptor hasn’t been found with feathers preserved yet, but based on its skeleton, that’s what the model predicts.
Can I use these diagrams or reconstructions for my own artwork?+
The diagrams and reference material on this page are owned by Answers in Genesis. If you’d like to use one, please email Joel for permission first.
Where can I learn more about maniraptoran anatomy?+
The conference slides and handout above walk through the anatomy in detail, and the Baraminer tool below lets you explore the underlying Turner et al. (2021) dataset yourself — comparing taxa and characters directly. The Turner et al. (2021) paper is cited throughout as the primary data source.